1. Field of the Invention
This invention relates to apparatus which is used to remove the marginal edges from metallic sheet or strip material moving along a pass line. More particularly, the invention concerns such apparatus wherein, a knife head at each of opposite sides of the material includes shear knives and a drive element for rotating the knives while the knife heads are canted to operate while applying lateral tension on the sheet or strip without the requirement for a separate drive housing and universal drive shaft.
2. Description of the Prior Art
It is well known to those skilled in the art that in the production of sheet or strip material, whether of steel or other metal, where the material is moved through a pass line and ultimately turned into a product in the form of a coil or a stack of sheets, there is provided in association with the pass line a means for trimming the marginal edges of the material to a desired, predetermined width. Usually, the means further includes scrap-chopper means located adjacent to the shear-knife means and slightly downstream thereof for the obvious purpose of chopping the removed edges into small pieces.
It has been known, moreover, to mount the shear-knife means on shafts that extend toward the middle of the pass line and meet in a coupling. In known equipment of this kind, the drive shafts are coaxially located by rigid shaft and cannot be canted. This is done for speed matching of the shear knives at both sides of the strip. It is desirable that the shear-knife means tends to exert on the strip or sheet which is being cut a transverse force which tends to keep the sheet or strip flattened at the vicinity of the cut and prevent the material from becoming bunched. The traverse force will also cause the scrap trim edge to deflect thereby into a scrap chopper.
Known equipment of this kind possesses two main drawbacks. First, there is an impairment to the accessibility to the shear knives when they require maintenance such as sharpening, adjustment, or replacement. Second, the coupling means and drive shafts which are in the vicinity of the center of the pass line must be perfectly aligned. Despite the existence of these drawbacks over several decades, the art has not, prior to the present invention, developed to the point of having means whereby these disadvantages can be avoided or overcome.